Vehicle air conditioner with changing operation mode

ABSTRACT

A vehicle air conditioner is capable of selecting and changing an optimum operation mode so that a desirable air conditioning performance can be exerted on conditions such as an environment and a set temperature. A controller changes and executes at least one of a heating mode, a dehumidifying and heating mode, a dehumidifying and cooling mode, and a cooling mode. In the dehumidifying and heating mode, the controller shifts to the dehumidifying and cooling mode on the basis of a situation where heat absorption in a heat absorber ( 9 ) runs short or heat radiation in a radiator ( 4 ) becomes excessive, and also in this dehumidifying and cooling mode, the controller shifts to the dehumidifying and heating mode on the basis of a situation where the heat radiation in the radiator ( 4 ) runs short.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Patent Application under 37U.S.C. §371 of International Patent Application No. PCT/JP2013/080472,filed on Nov. 11, 2013, which claims the benefit of Japanese PatentApplication No. JP 2012-247491, filed on Nov. 9, 2012, the disclosuresof which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to an air conditioner of a heat pumpsystem which conditions air in a vehicle interior, and moreparticularly, it relates to an air conditioner applicable to a hybridcar or an electric car.

BACKGROUND ART

Due to actualization of environmental problems in recent years, hybridcars and electric cars have spread. Furthermore, as an air conditionerwhich is applicable to such a vehicle, there has been developed an airconditioner which comprises a compressor to compress and discharge arefrigerant, a radiator disposed on a vehicle interior side to let therefrigerant radiate heat, a heat absorber disposed on the vehicleinterior side to let the refrigerant absorb heat, and an outdoor heatexchanger disposed outside the vehicle interior to let the refrigerantradiate or absorb heat, and which can change a heating operation inwhich the refrigerant discharged from the compressor radiates heat inthe radiator and the refrigerant by which heat has been radiated in thisradiator absorbs heat in the outdoor heat exchanger, a dehumidifying andheating operation in which the refrigerant discharged from thecompressor radiates heat in the radiator and the refrigerant by whichheat has been radiated in the radiator absorbs heat only in the heatabsorber or in this heat absorber and the outdoor heat exchanger, acooling operation in which the refrigerant discharged from thecompressor radiates heat in the outdoor heat exchanger and absorbs heatin the heat absorber, and a dehumidifying and cooling operation in whichthe refrigerant discharged from the compressor radiates heat in theradiator and the outdoor heat exchanger and absorbs heat in the heatabsorber (e.g., see Patent Document 1).

CITATION LIST Patent Documents

Patent Document 1: Japanese Patent Application Publication No.2012-176659

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In the above conventional vehicle air conditioner, a mode of each of theabove heating operation, dehumidifying and heating operation, coolingoperation and dehumidifying and cooling operation is selected andchanged in accordance with a combination of an outdoor air temperatureTam and a target outlet temperature TAO (a target value of a temperatureof air blown out into a vehicle interior).

Here, on conditions such as an environment of a vehicle and a settemperature, an optimum operation mode is present in the airconditioner, but in such conventional mode changing control, there hasbeen the problem that the optimum operation mode is not necessarilyselected. Furthermore, when an unsuitable operation mode is selected, adesirable air conditioning performance cannot be exerted, andcomfortable air condition in the vehicle interior cannot be realized.

The present invention has been developed to solve these conventionaltechnical problems, and an object thereof is to provide a vehicle airconditioner which is capable of selecting and changing an optimumoperation mode so that a desirable air conditioning performance can beexerted on conditions such as an environment and a set temperature.

Means for Solving the Problems

A vehicle air conditioner of the present invention comprises acompressor which compresses a refrigerant, an air flow passage throughwhich air to be supplied into a vehicle interior flows, a radiatordisposed in this air flow passage to let the refrigerant radiate heat, aheat absorber disposed in the air flow passage to let the refrigerantabsorb heat, an outdoor heat exchanger disposed outside the vehicleinterior to let the refrigerant radiate or absorb heat, and controlmeans, this control means being configured to change and execute atleast one of a heating mode in which the refrigerant discharged from thecompressor radiates heat in the radiator and the refrigerant by whichheat has been radiated is decompressed and then absorbs heat in theoutdoor heat exchanger, a dehumidifying and heating mode in which therefrigerant discharged from the compressor radiates heat in the radiatorand the refrigerant by which heat has been radiated is decompressed andthen absorbs heat only in the heat absorber or in the heat absorber andthe outdoor heat exchanger, a dehumidifying and cooling mode in whichthe refrigerant discharged from the compressor radiates heat in theradiator and the outdoor heat exchanger and the refrigerant by whichheat has been radiated is decompressed and then absorbs heat in the heatabsorber, and a cooling mode in which the refrigerant discharged fromthe compressor radiates heat in the outdoor heat exchanger and therefrigerant by which heat has been radiated is decompressed and thenabsorbs heat in the heat absorber, the vehicle air conditioner beingcharacterized in that the control means shifts to the dehumidifying andcooling mode on the basis of a situation where heat absorption in theheat absorber runs short or heat radiation in the radiator becomesexcessive in the dehumidifying and heating mode, and also shifts to thedehumidifying and heating mode on the basis of a situation where theheat radiation in the radiator runs short in this dehumidifying andcooling mode.

The vehicle air conditioner of the invention of claim 2 is characterizedin that in the above invention, the control means has, in thedehumidifying and heating mode, an internal cycle mode in which therefrigerant is inhibited from flowing into the outdoor heat exchangerand the refrigerant absorbs heat only in the heat absorber, shifts tothe internal cycle mode on the basis of a situation where the heatabsorption in the heat absorber runs short or the heat radiation in theradiator becomes excessive in the dehumidifying and heating mode, andalso shifts to the dehumidifying and cooling mode on the basis of asituation where the heat absorption in the heat absorber further runsshort or the heat radiation in the radiator further becomes excessive inthis internal cycle mode.

The vehicle air conditioner of the invention of claim 3 is characterizedin that in the above invention, the control means shifts to the internalcycle mode on the basis of the situation where the heat radiation in theradiator runs short in the dehumidifying and cooling mode, and alsoshifts to the dehumidifying and heating mode on the basis of thesituation where the heat radiation in the radiator runs short or theheat absorption in the heat absorber becomes excessive in this internalcycle mode.

The vehicle air conditioner of the invention of claim 4 is characterizedin that in the above respective inventions, the control means shiftsfrom the heating mode to the dehumidifying and heating mode or thedehumidifying and cooling mode on the basis of a situation where anoutdoor air temperature and an outdoor air humidity rise, and shiftsfrom the dehumidifying and heating mode and the dehumidifying andcooling mode to the heating mode on the basis of a situation where theoutdoor air temperature and the outdoor air humidity lower.

The vehicle air conditioner of the invention of claim 5 is characterizedin that in the above invention, the control means shifts from theheating mode to the dehumidifying and cooling mode on the basis of asituation where the outdoor air temperature rises to a temperaturehigher than a temperature of a condition for the shift from the heatingmode to the dehumidifying and heating mode.

The vehicle air conditioner of the invention of claim 6 comprises anexpansion valve which decompresses the refrigerant flowing into theoutdoor heat exchanger in the above respective inventions, and ischaracterized in that the control means shifts from the dehumidifyingand cooling mode to the cooling mode on the basis of a situation where avalve position of the expansion valve reaches an upper limit ofcontrolling, and shifts from the cooling mode to the dehumidifying andcooling mode on the basis of the situation where the heat radiation inthe radiator runs short.

The vehicle air conditioner of the invention of claim 7 comprises, inthe above respective inventions, a suction changing damper which changesan outdoor air introducing mode to introduce the outdoor air into theair flow passage and an indoor air circulating mode to introduce the airin the vehicle interior into the air flow passage, and is characterizedin that when the control means executes the heating mode or thedehumidifying and heating mode on startup, the control means transfersthe suction changing damper to the outdoor air introducing mode in acase where at least the outdoor air temperature is higher than aninterior temperature or at least an interior humidity is higher than theoutdoor air humidity, and to the indoor air circulating mode in a casewhere at least the interior temperature is higher than the outdoor airtemperature or at least the outdoor air humidity is higher than theinterior humidity.

The vehicle air conditioner of the invention of claim 8 comprises, inthe above respective inventions, a suction changing damper which changesan outdoor air introducing mode to introduce the outdoor air into theair flow passage and an indoor air circulating mode to introduce the airin the vehicle interior into the air flow passage, and is characterizedin that when the control means executes the cooling mode or thedehumidifying and cooling mode on the startup, the control meanstransfers the suction changing damper to the indoor air circulating modein a case where at least the outdoor air temperature is higher than theinterior temperature or at least the outdoor air humidity is higher thanthe interior humidity, and to the outdoor air introducing mode in a casewhere at least the interior temperature is higher than the outdoor airtemperature or at least the interior humidity is higher than the outdoorair humidity.

The vehicle air conditioner of the invention of claim 9 is characterizedin that in the invention of claim 7 or claim 8, in a stable conditionafter the start, the control means transfers the suction changing damperto the outdoor air introducing mode in a case where a carbon dioxideconcentration in the vehicle interior is high, or the indoor aircirculating mode is continued for a predetermined time or more, or theinterior humidity is higher than the outdoor air humidity, or a targetvalue of a temperature of the air blown out into the vehicle interior isthe same as or close to the outdoor air temperature, and the controlmeans transfers the suction changing damper to the indoor aircirculating mode on conditions other than the above conditions.

Advantageous Effect of the Invention

According to the present invention, a vehicle air conditioner comprisesa compressor which compresses a refrigerant, an air flow passage throughwhich air to be supplied into a vehicle interior flows, a radiatordisposed in this air flow passage to let the refrigerant radiate heat, aheat absorber disposed in the air flow passage to let the refrigerantabsorb heat, an outdoor heat exchanger disposed outside the vehicleinterior to let the refrigerant radiate or absorb heat, and controlmeans. This control means is configured to change and execute at leastone of a heating mode in which the refrigerant discharged from thecompressor radiates heat in the radiator, and the refrigerant by whichheat has been radiated is decompressed and then absorbs heat in theoutdoor heat exchanger, a dehumidifying and heating mode in which therefrigerant discharged from the compressor radiates heat in theradiator, and the refrigerant by which heat has been radiated isdecompressed and then absorbs heat only in the heat absorber or in theheat absorber and the outdoor heat exchanger, a dehumidifying andcooling mode in which the refrigerant discharged from the compressorradiates heat in the radiator and the outdoor heat exchanger and therefrigerant by which heat has been radiated is decompressed and thenabsorbs heat in the heat absorber, and a cooling mode in which therefrigerant discharged from the compressor radiates heat in the outdoorheat exchanger, and the refrigerant by which heat has been radiated isdecompressed and then absorbs heat in the heat absorber. In the vehicleair conditioner, the control means shifts to the dehumidifying andcooling mode on the basis of a situation where heat absorption in theheat absorber runs short or heat radiation in the radiator becomesexcessive in the dehumidifying and heating mode, and also shifts to thedehumidifying and heating mode on the basis of a situation where theheat radiation in the radiator runs short in this dehumidifying andcooling mode. Therefore, it is possible to accurately change anoperation mode between the dehumidifying and heating mode and thedehumidifying and cooling mode in accordance with the situation wherethe heat radiation in the radiator or the heat absorption in the heatabsorber runs short or becomes excessive on conditions such as anenvironment of the vehicle and a set temperature.

Furthermore, according to the invention of claim 2, in addition to theabove invention, when the control means has, in the dehumidifying andheating mode, an internal cycle mode in which the refrigerant isinhibited from flowing into the outdoor heat exchanger and therefrigerant absorbs heat only in the heat absorber, the control meansshifts to the internal cycle mode on the basis of a situation where theheat absorption in the heat absorber runs short or the heat radiation inthe radiator becomes excessive in the dehumidifying and heating mode,and also shifts to the dehumidifying and cooling mode on the basis of asituation where the heat absorption in the heat absorber further runsshort or the heat radiation in the radiator further becomes excessive inthis internal cycle mode. Therefore, it is possible to accurately changethe operation mode from the dehumidifying and heating mode to theinternal cycle mode and further from the internal cycle mode to thedehumidifying and cooling mode in accordance with the situation of theheat absorption in the heat absorber or the heat radiation in theradiator.

Additionally, according to the invention of claim 3, in addition to theabove invention, the control means shifts to the internal cycle mode onthe basis of the situation where the heat radiation in the radiator runsshort in the dehumidifying and cooling mode, and also shifts to thedehumidifying and heating mode on the basis of the situation where theheat radiation in the radiator runs short or the heat absorption in theheat absorber becomes excessive in this internal cycle mode. Therefore,it is possible to accurately change the operation mode from thedehumidifying and cooling mode to the internal cycle mode and furtherfrom the internal cycle mode to the dehumidifying and heating mode inaccordance with the situation of the heat radiation in the radiator orthe heat absorption in the heat absorber.

Furthermore, according to the invention of claim 4, in addition to theabove respective inventions, the control means shifts from the heatingmode to the dehumidifying and heating mode or the dehumidifying andcooling mode on the basis of a situation where an outdoor airtemperature and an outdoor air humidity rise, and shifts from thedehumidifying and heating mode and the dehumidifying and cooling mode tothe heating mode on the basis of a situation where the outdoor airtemperature and the outdoor air humidity lower. Therefore, it ispossible to accurately change the operation mode among the heating mode,the dehumidifying and heating mode and the dehumidifying and coolingmode in accordance with an outdoor air environment.

Additionally, according to the invention of claim 5, in addition to theabove invention, the control means shifts from the heating mode to thedehumidifying and cooling mode on the basis of a situation where theoutdoor air temperature rises to a temperature higher than a temperatureof a condition for the shift from the heating mode to the dehumidifyingand heating mode. Therefore, it is possible to shift from the heatingmode directly to the dehumidifying and cooling mode in a situation wherethe temperature further rises in the outdoor air environment.

Furthermore, according to the invention of claim 6, in addition to theabove respective inventions, the vehicle air conditioner comprises anexpansion valve which decompresses the refrigerant flowing into theoutdoor heat exchanger, and the control means shifts from thedehumidifying and cooling mode to the cooling mode on the basis of asituation where a valve position of the expansion valve reaches an upperlimit of controlling, and shifts from the cooling mode to thedehumidifying and cooling mode on the basis of a situation where theheat radiation in the radiator runs short. Therefore, it is possible toaccurately change the operation mode between the cooling mode and thedehumidifying and cooling mode in accordance with a control situation ofthe expansion valve or the situation of the heat radiation of theradiator.

Additionally, according to the invention of claim 7, in addition to theabove respective inventions, the vehicle air conditioner comprises asuction changing damper which changes an outdoor air introducing mode tointroduce the outdoor air into the air flow passage and an indoor aircirculating mode to introduce the air in the vehicle interior into theair flow passage, and is characterized in that when the control meansexecutes the heating mode or the dehumidifying and heating mode onstartup, the control means transfers the suction changing damper to theoutdoor air introducing mode in a case where at least the outdoor airtemperature is higher than an interior temperature or at least aninterior humidity is higher than the outdoor air humidity, and to theindoor air circulating mode in a case where at least the interiortemperature is higher than the outdoor air temperature or at least theoutdoor air humidity is higher than the interior humidity. Therefore,when the heating mode or the dehumidifying and heating mode is executedon the startup, it is possible to accurately change the outdoor airintroducing mode and the indoor air circulating mode in accordance withthe outdoor air environment and effectively utilize heat in the outdoorair for the heating in the vehicle.

Furthermore, according to the invention of claim 8, in addition to theabove respective inventions, the vehicle air conditioner comprises asuction changing damper which changes an outdoor air introducing mode tointroduce the outdoor air into the air flow passage and an indoor aircirculating mode to introduce the air in the vehicle interior into theair flow passage. When the control means executes the cooling mode orthe dehumidifying and cooling mode on the startup, the control meanstransfers the suction changing damper to the indoor air circulating modein a case where at least the outdoor air temperature is higher than aninterior temperature or at least the outdoor air humidity is higher thanan interior humidity, and to the outdoor air introducing mode in a casewhere at least the interior temperature is higher than the outdoor airtemperature or at least the interior humidity is higher than the outdoorair humidity. Therefore, when the cooling mode or the dehumidifying andcooling mode is executed on the startup, the outdoor air introducingmode and the indoor air circulating mode are accurately changed inaccordance with the outdoor air environment, so that it is possible toeliminate a bad influence of the heat in the outdoor air on the coolingin the vehicle, or effectively utilize cold in the outdoor air for thecooling in the vehicle.

In this case, as in the invention of claim 9, in the stable conditionafter the start, the control means transfers the suction changing damperto the outdoor air introducing mode in a case where a carbon dioxideconcentration in the vehicle interior is high, or the indoor aircirculating mode is continued for a predetermined time or more, or theinterior humidity is higher than the outdoor air humidity, or a targetvalue of a temperature of the air blown out into the vehicle interior isthe same as or close to the outdoor air temperature, and the controlmeans transfers the suction changing damper to the indoor aircirculating mode on conditions other than the above conditions.Therefore, it is possible to accurately change the outdoor airintroducing mode and the indoor air circulating mode also in accordancewith the carbon dioxide concentration in the vehicle interior or atarget outlet temperature in the stable condition.

As described above, according to the vehicle air conditioner of thepresent invention, it is possible to select and change an optimumoperation mode so that a desirable air conditioning performance can beexerted on conditions such as an environment of the vehicle or a settemperature, and the desirable air conditioning performance is exertedso that comfortable air condition in the vehicle can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a constitutional view of a vehicle air conditioner of oneembodiment to which the present invention is applied;

FIG. 2 is a block diagram of an electric circuit of a controller of thevehicle air conditioner of FIG. 1;

FIG. 3 is a control block diagram concerning compressor control of thecontroller of FIG. 2;

FIG. 4 is another control block diagram concerning the compressorcontrol of the controller of FIG. 2;

FIG. 5 is a control block diagram concerning outdoor expansion valvecontrol of the controller of FIG. 2;

FIG. 6 is a diagram to explain an operation mode on startup of thecontroller of FIG. 2;

FIG. 7 is a diagram to explain changing control of the operation mode bythe controller of FIG. 2;

FIG. 8 is a diagram to explain another example of the changing controlof the operation mode by the controller of FIG. 2;

FIG. 9 is a diagram to explain control of a suction changing damper bythe controller of FIG. 2;

FIG. 10 is a diagram to explain the changing control of a normal modeand a radiator temperature prior mode in a dehumidifying and coolingmode by the controller of FIG. 2;

FIG. 11 is a control block diagram of the controller in the radiatortemperature prior mode of FIG. 10;

FIG. 12 is a timing chart showing the changing control of the normalmode and the radiator temperature prior mode in the dehumidifying andcooling mode of FIG. 10;

FIG. 13 is a diagram to explain another example of the changing controlof the normal mode and the radiator temperature prior mode in thedehumidifying and cooling mode by the controller of FIG. 2;

FIG. 14 is a flowchart to explain the changing control of FIG. 13;

FIG. 15 is a control block diagram of the controller in the radiatortemperature prior mode of FIG. 13;

FIG. 16 is a diagram to explain still another example of the changingcontrol of the normal mode and the radiator temperature prior mode inthe dehumidifying and cooling mode by the controller of FIG. 2;

FIG. 17 is a flowchart to explain the changing control of FIG. 16;

FIG. 18 is a control block diagram of the controller in the radiatortemperature prior mode of FIG. 16;

FIG. 19 is a diagram to explain a further example of the changingcontrol of the normal mode and the radiator temperature prior mode inthe dehumidifying and cooling mode by the controller of FIG. 2;

FIG. 20 is a flowchart to explain the changing control of FIG. 19;

FIG. 21 is a flowchart to explain another example of the changingcontrol of FIG. 19; and

FIG. 22 is a control block diagram of the controller in the radiatortemperature prior mode of FIG. 21.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described indetail with reference to the drawings.

FIG. 1 shows a constitutional view of a vehicle air conditioner 1 of oneembodiment of the present invention. In this case, a vehicle of theembodiment to which the present invention is applied is an electric car(EV) which does not have an engine (an internal combustion engine), andruns by driving an electric motor for running by a power charged in abattery (which is not shown), and the vehicle air conditioner 1 of thepresent invention is driven by the power of the battery.

That is, in the electric car in which heating cannot be performed bywaste heat of the engine, the vehicle air conditioner 1 of theembodiment performs the heating by a heat pump operation in which arefrigerant circuit is used, and further selectively executes respectiveoperation modes of dehumidifying and heating, cooling and dehumidifying,cooling, and the like. It is to be noted that the vehicle is not limitedto the electric car, and the present invention is also effective for aso-called hybrid car in which the engine is used together with theelectric motor for the running, and is further applicable also to ausual car which runs by the engine.

The vehicle air conditioner 1 of the embodiment performs airconditioning (heating, cooling, dehumidifying, and ventilation) in theelectric car, and there are successively connected, by a refrigerantpipe 13, an electric compressor 2 which compresses a refrigerant toraise a pressure, a radiator 4 disposed in an air flow passage 3 of anHVAC unit 10 in which air in the vehicle interior is passed andcirculated, to let the high-temperature high-pressure refrigerantdischarged from the compressor 2 radiate heat in the vehicle interior,an outdoor expansion valve 6 constituted of an electric valve whichdecompresses and expands the refrigerant during the heating, an outdoorheat exchanger 7 which performs heat exchange between the refrigerantand outdoor air to function as the radiator during the cooling andfunction as an evaporator during the heating, an indoor expansion valve8 constituted of an electric valve which decompresses and expands therefrigerant, a heat absorber 9 disposed in the air flow passage 3 to letthe refrigerant absorb heat from interior and exterior of the vehicleduring the cooling and during the dehumidifying and heating, anevaporation capability control valve 11 which regulates an evaporationcapability in the heat absorber 9, an accumulator 12 and the like, sothat a refrigerant circuit R is constituted. It is to be noted that inthe outdoor heat exchanger 7, an outdoor blower 15 is disposed toperform the heat exchange between the outdoor air and the refrigerantwhen the vehicle is stopped.

In addition, the outdoor heat exchanger 7 has a header portion 14 and asubcooling portion 16 successively on a refrigerant downstream side, arefrigerant pipe 13A extended out from the outdoor heat exchanger 7 isconnected to the header portion 14 via a solenoid valve (anopening/closing valve) 17 opened during the cooling, and an outlet ofthe subcooling portion 16 is connected to the indoor expansion valve 8via a check valve 18. It is to be noted that the header portion 14 andthe subcooling portion 16 structurally constitute a part of the outdoorheat exchanger 7, and an indoor expansion valve 8 side of the checkvalve 18 is a forward direction.

In addition, a refrigerant pipe 13B between the check valve 18 and theindoor expansion valve 8 is disposed in a heat exchange relation with arefrigerant pipe 13C extended out from the evaporation capabilitycontrol valve 11 positioned on an outlet side of the heat absorber 9,and both the pipes constitute an internal heat exchanger 19. Inconsequence, the refrigerant flowing through the refrigerant pipe 13Binto the indoor expansion valve 8 is cooled (subcooled) by thelow-temperature refrigerant flowing out from the heat absorber 9 throughthe evaporation capability control valve 11.

In addition, the refrigerant pipe 13A extended out from the outdoor heatexchanger 7 is branched, and this branched refrigerant pipe 13Dcommunicates to be connected to the refrigerant pipe 13C on thedownstream side of the internal heat exchanger 19 via a solenoid valve(an opening/closing valve) 21 to be opened during heating. Furthermore,a refrigerant pipe 13E on an outlet side of the radiator 4 is branchedbefore the outdoor expansion valve 6, and this branched refrigerant pipe13F communicates to be connected to the refrigerant pipe 13B on thedownstream side of the check valve 18 via a solenoid valve (anopening/closing valve) 22 to be opened during the dehumidifying.

In addition, a refrigerant pipe 13G on a discharge side of thecompressor 2 is branched, and this branched refrigerant pipe 13Hcommunicates to be connected to a refrigerant pipe 13I between theoutdoor expansion valve 6 and the outdoor heat exchanger 7 via asolenoid valve (an opening/closing valve) 23 which is opened duringdefrosting of the outdoor heat exchanger 7 to allow the high-temperaturerefrigerant (a hot gas) discharged from the compressor 2 to flowdirectly into the outdoor heat exchanger 7 and a check valve 24. It isto be noted that a direction of the refrigerant pipe 13I of the checkvalve 24 is the forward direction.

Additionally, in the air flow passage 3 on an air upstream side of theheat absorber 9, respective suction ports (represented by a suction port25 in FIG. 1), e.g., an indoor air suction port and an outdoor airsuction port are formed, and in the suction port 25, a suction changingdamper 26 is disposed to change the air to be introduced into the airflow passage 3 to indoor air which is air in the vehicle interior (anindoor air circulating mode) and outdoor air which is air outside thevehicle interior (an outdoor air introducing mode). Further, on an airdownstream side of the suction changing damper 26, an indoor blower (ablower fan) 27 is disposed to supply the introduced indoor air oroutdoor air to the air flow passage 3.

Additionally, in the air flow passage 3 on the air upstream side of theradiator 4, an air mix damper 28 is disposed to regulate a degree offlow of the indoor air or the outdoor air through the radiator 4.Further, in the air flow passage 3 on an air downstream side of theradiator 4, each outlet of foot, vent or defroster (represented by anoutlet 29 in FIG. 1) is formed, and in the outlet 29, an outlet changingdamper 31 is disposed to perform changing control of blowing of the airfrom each outlet mentioned above.

Next, in FIG. 2, 32 is a controller (ECU) as control means constitutedof a microcomputer, and an input of the controller 32 is connected torespective outputs of an outdoor air temperature sensor 33 which detectsan outdoor air temperature of the vehicle, an outdoor air humiditysensor 34 which detects an outdoor air humidity, an HVAC suctiontemperature sensor 36 which detects a suction temperature from thesuction port 25 to the air flow passage 3, an indoor air temperaturesensor 37 which detects a temperature of the air in the vehicle interior(the indoor air), an indoor air humidity sensor 38 which detects ahumidity of the air in the vehicle interior, an indoor air CO₂concentration sensor 39 which detects a carbon dioxide concentration inthe vehicle interior, an outlet temperature sensor 41 which detects atemperature of the air blown out from the outlet 29 into the vehicleinterior, a discharge pressure sensor 42 which detects a pressure of therefrigerant discharged from the compressor 2, a discharge temperaturesensor 43 which detects a temperature of the refrigerant discharged fromthe compressor 2, a suction pressure sensor 44 which detects a suctionrefrigerant pressure of the compressor 2, a radiator temperature sensor46 which detects a temperature of the radiator 4 (the temperature of theradiator 4 itself or the temperature of the air heated in the radiator4), a radiator pressure sensor 47 which detects a refrigerant pressureof the radiator 4 (the pressure in the radiator 4 or the pressure of therefrigerant flowing out from the radiator 4), a heat absorbertemperature sensor 48 which detects a temperature of the heat absorber 9(the temperature of the heat absorber 9 itself or the air cooled in theheat absorber 9), a heat absorber pressure sensor 49 which detects arefrigerant pressure of the heat absorber 9 (the pressure in the heatabsorber 9 or the pressure of the refrigerant flowing out from the heatabsorber 9), a solar radiation sensor 51 of, e.g., a photo sensor systemto detect a solar radiation amount into the vehicle, a velocity sensor52 to detect a moving speed of the vehicle (a velocity), an operatingportion 53 to set the changing of the temperature or the operation mode,an outdoor heat exchanger temperature sensor 54 which detects atemperature of the outdoor heat exchanger 7, and an outdoor heatexchanger pressure sensor 56 which detects the refrigerant pressure ofthe outdoor heat exchanger 7.

An output of the controller 32 is connected to the compressor 2, theoutdoor blower 15, the indoor blower (the blower fan) 27, the suctionchanging damper 26, the air mix damper 28, the outlet changing damper31, the outdoor expansion valve 6, the indoor expansion valve 8, therespective solenoid valves 23, 22, 17 and 21, and the evaporationcapability control valve 11. In addition, the output of the controller32 is also connected to an electric heater 57 disposed in the air flowpassage 3 on the air downstream side of the radiator 4 to complement theheating by the radiator 4, and the controller 32 controls thesecomponents on the basis of the outputs of the respective sensors and thesetting input by the operating portion 53.

Next, an operation of the vehicle air conditioner 1 of the embodimenthaving the abovementioned constitution will be described. In theembodiment, the controller 32 changes and executes respective roughlydivided operation modes such as a heating mode, a dehumidifying andheating mode, an internal cycle mode, a dehumidifying and cooling mode,and a cooling mode. First, the flow of the refrigerant in each operationmode will be described.

(1) Heating Mode

When the heating mode is selected by the controller 32 or a manualoperation to the operating portion 53, the controller 32 opens thesolenoid valve 21 and closes the solenoid valve 17, the solenoid valve22 and the solenoid valve 23. Furthermore, the compressor 2 and therespective blowers 15 and 27 are operated, and the air mix damper 28 hasa state where the air blown out from the indoor blower 27 is passedthrough the radiator 4. In consequence, the high-temperaturehigh-pressure gas refrigerant discharged from the compressor 2 flowsinto the radiator 4. The air in the air flow passage 3 is passed throughthe radiator 4, and hence the air in the air flow passage 3 is heated bythe high-temperature refrigerant in the radiator 4, whereas therefrigerant in the radiator 4 has the heat taken by the air and iscooled to condense and liquefy.

The refrigerant liquefied in the radiator 4 flows through therefrigerant pipe 13E to reach the outdoor expansion valve 6 whichdecompresses the refrigerant, and then the refrigerant flows into theoutdoor heat exchanger 7. The refrigerant flowing into the outdoor heatexchanger 7 evaporates, and the heat is pumped up from the outdoor airpassed by running or the outdoor blower 15 (a heat pump). Furthermore,the low-temperature refrigerant flowing out from the outdoor heatexchanger 7 flows through the refrigerant pipe 13D and the solenoidvalve 21 to flow from the refrigerant pipe 13C into the accumulator 12in which gas liquid separation is performed, and then the gasrefrigerant is sucked into the compressor 2, thereby repeating thiscirculation. The air heated in the radiator 4 is blown out from theoutlet 29, and hence the heating in the vehicle interior is performed.

The controller 32 controls a revolution number of the compressor 2 onthe basis of a high pressure of the refrigerant circuit R which isdetected by the discharge pressure sensor 42 or the radiator pressuresensor 47, also controls a valve position of the outdoor expansion valve6 on the basis of the temperature of the radiator 4 which is detected bythe radiator temperature sensor 46 and the refrigerant pressure of theradiator 4 which is detected by the radiator pressure sensor 47, andcontrols a subcool degree of the refrigerant in the outlet of theradiator 4.

(2) Dehumidifying and Heating Mode

Next, in the dehumidifying and heating mode, the controller 32 opens thesolenoid valve 22 in the above state of the heating mode. Inconsequence, a part of the condensed refrigerant flowing through theradiator 4 and the refrigerant pipe 13E is distributed, and flowsthrough the solenoid valve 22 to flow from the refrigerant pipes 13F and13B through the internal heat exchanger 19, thereby reaching the indoorexpansion valve 8. The refrigerant is decompressed in the indoorexpansion valve 8 and then flows into the heat absorber 9 to evaporate.Water in the air blown out from the indoor blower 27 coagulates toadhere to the heat absorber 9 by a heat absorbing operation at thistime, and hence the air is cooled and dehumidified.

The refrigerant evaporated in the heat absorber 9 flows through theevaporation capability control valve 11 and the internal heat exchanger19 to join the refrigerant from the refrigerant pipe 13D in therefrigerant pipe 13C, and then flows through the accumulator 12 to besucked into the compressor 2, thereby repeating this circulation. Theair dehumidified in the heat absorber 9 is reheated in a process ofpassing the radiator 4, and hence the dehumidifying and heating in thevehicle interior are performed.

The controller 32 controls the revolution number of the compressor 2 onthe basis of the high pressure of the refrigerant circuit R which isdetected by the discharge pressure sensor 42 or the radiator pressuresensor 47, and also controls the valve position of the outdoor expansionvalve 6 on the basis of the temperature of the heat absorber 9 which isdetected by the heat absorber temperature sensor 48.

(3) Internal Cycle Mode

Next, in the internal cycle mode, the controller 32 closes (shuts off)the outdoor expansion valve 6 in the above state of the dehumidifyingand heating mode. That is, it can be considered that this internal cyclemode is a state where the outdoor expansion valve 6 is shut off by thecontrol of the outdoor expansion valve 6 in the dehumidifying andheating mode, and hence the internal cycle mode can be regarded as apart of the dehumidifying and heating mode.

However, when the outdoor expansion valve 6 is closed, the refrigerantis inhibited from flowing into the outdoor heat exchanger 7, and henceall the condensed refrigerant flowing through the radiator 4 and therefrigerant pipe 13E flows through the solenoid valve 22 to therefrigerant pipe 13F. Furthermore, the refrigerant flowing through therefrigerant pipe 13F flows from the refrigerant pipe 13B through theinternal heat exchanger 19 to reach the indoor expansion valve 8. Therefrigerant is decompressed in the indoor expansion valve 8 and thenflows into the heat absorber 9 to evaporate. The water in the air blownout from the indoor blower 27 coagulates to adhere to the heat absorber9 by the heat absorbing operation at this time, and hence the air iscooled and dehumidified.

The refrigerant evaporated in the heat absorber 9 flows through theevaporation capability control valve 11, the internal heat exchanger 19,the refrigerant pipe 13C and the accumulator 12 to be sucked into thecompressor 2, thereby repeating this circulation. The air dehumidifiedin the heat absorber 9 is reheated in the process of passing theradiator 4, and hence the dehumidifying and heating in the vehicleinterior are performed. However, in this internal cycle mode, therefrigerant is circulated between the radiator 4 (heat radiation) andthe heat absorber 9 (heat absorption) which are present in the air flowpassage 3 on an indoor side, and hence the heat is not pumped up fromthe outdoor air, but a heating capability for consumed power of thecompressor 2 is exerted. The whole amount of the refrigerant flowsthrough the heat absorber 9 which exerts a dehumidifying operation, andhence as compared with the above dehumidifying and heating mode, adehumidifying capability is high, but the heating capability lowers.

The controller 32 controls the revolution number of the compressor 2 onthe basis of the temperature of the heat absorber 9 or theabovementioned high pressure of the refrigerant circuit R. At this time,the controller 32 selects a smaller compressor target number ofrevolution from compressor target numbers of revolution obtained bycalculations from the temperature of the heat absorber 9 or the highpressure, to control the compressor 2 as described later.

(4) Dehumidifying and Cooling Mode

Next, in the dehumidifying and cooling mode, the controller 32 opens thesolenoid valve 17 and closes the solenoid valve 21, the solenoid valve22 and the solenoid valve 23. Furthermore, the compressor 2 and therespective blowers 15 and 27 are operated, and the air mix damper 28 hasthe state where the air blown out from the indoor blower 27 is passedthrough the radiator 4. In consequence, the high-temperaturehigh-pressure gas refrigerant discharged from the compressor 2 flowsinto the radiator 4. Through the radiator 4, the air in the air flowpassage 3 is passed, and hence the air in the air flow passage 3 isheated by the high-temperature refrigerant in the radiator 4, whereasthe refrigerant in the radiator 4 has the heat taken by the air and iscooled to condense and liquefy.

The refrigerant flowing out from the radiator 4 flows through therefrigerant pipe 13E to reach the outdoor expansion valve 6, and flowsthrough the outdoor expansion valve 6 controlled so that the valve tendsto be open, to flow into the outdoor heat exchanger 7. The refrigerantflowing into the outdoor heat exchanger 7 is cooled by the runningtherein or the outdoor air passed by the outdoor blower 15, to condense.The refrigerant flowing out from the outdoor heat exchanger 7 flows fromthe refrigerant pipe 13A through the solenoid valve 17 to successivelyflow into the header portion 14 and the subcooling portion 16. Here, therefrigerant is subcooled.

The refrigerant flowing out from the subcooling portion 16 of theoutdoor heat exchanger 7 flows through the check valve 18 to enter therefrigerant pipe 13B, and flows through the internal heat exchanger 19to reach the indoor expansion valve 8. The refrigerant is decompressedin the indoor expansion valve 8 and then flows into the heat absorber 9to evaporate. The water in the air blown out from the indoor blower 27coagulates to adhere to the heat absorber 9 by the heat absorbingoperation at this time, and hence the air is cooled and dehumidified.

The refrigerant evaporated in the heat absorber 9 flows through theevaporation capability control valve 11, the internal heat exchanger 19and the refrigerant pipe 13C to reach the accumulator 12, and flowstherethrough to be sucked into the compressor 2, thereby repeating thiscirculation. The air cooled and dehumidified in the heat absorber 9 isreheated in the process of passing the radiator 4 (a radiationcapability is lower than that during the heating), and hence thedehumidifying and cooling in the vehicle interior are performed.

The controller 32 controls the revolution number of the compressor 2 onthe basis of the temperature of the heat absorber 9 which is detected bythe heat absorber temperature sensor 48, also controls the valveposition of the outdoor expansion valve 6 on the basis of theabovementioned high pressure of the refrigerant circuit R, and controlsa refrigerant pressure (an after-mentioned radiator pressure PCI) of theradiator 4.

(5) Cooling Mode

Next, in the cooling mode, the controller 32 fully opens the outdoorexpansion valve 6 in the above state of the dehumidifying and coolingmode (sets the valve position to an upper limit of controlling), and theair mix damper 28 has a state where the air is not passed through theradiator 4. In consequence, the high-temperature high-pressure gasrefrigerant discharged from the compressor 2 flows into the radiator 4.The air in the air flow passage 3 is not passed through the radiator 4,the air therefore only passes here, and the refrigerant flowing out fromthe radiator 4 flows through the refrigerant pipe 13E to reach theoutdoor expansion valve 6.

At this time, the outdoor expansion valve 6 is fully opened and hencethe refrigerant flows into the outdoor heat exchanger 7 as it is, inwhich the refrigerant is cooled by the running therein or the outdoorair passed through the outdoor blower 15, to condensate and liquefy. Therefrigerant flowing out from the outdoor heat exchanger 7 flows from therefrigerant pipe 13A through the solenoid valve 17 to successively flowinto the header portion 14 and the subcooling portion 16. Here, therefrigerant is subcooled.

The refrigerant flowing out from the subcooling portion 16 of theoutdoor heat exchanger 7 flows through the check valve 18 to enter therefrigerant pipe 13B, and flows through the internal heat exchanger 19to reach the indoor expansion valve 8. The refrigerant is decompressedin the indoor expansion valve 8 and then flows into the heat absorber 9to evaporate. The water in the air blown out from the indoor blower 27coagulates to adhere to the heat absorber 9 by the heat absorbingoperation at this time, so that the air is cooled.

The refrigerant evaporated in the heat absorber 9 flows through theevaporation capability control valve 11, the internal heat exchanger 19and the refrigerant pipe 13C to reach the accumulator 12, and flowstherethrough to be sucked into the compressor 2, thereby repeating thiscirculation. The air cooled and dehumidified in the heat absorber 9 doesnot pass the radiator 4 but is blown out from the outlet 29 into thevehicle interior, and hence cooling in the vehicle interior isperformed.

In this cooling mode, the controller 32 controls the revolution numberof the compressor 2 on the basis of the temperature of the heat absorber9 which is detected by the heat absorber temperature sensor 48. Next,FIG. 3 to FIG. 5 show control block diagrams of the compressor 2 and theoutdoor expansion valve 6 by the controller 32 in the abovementionedrespective operation modes. FIG. 3 is the control block diagram of thecontroller 32 which determines a target number of revolution (acompressor target number of revolution) TGNCh of the compressor 2 forthe above heating mode and the above dehumidifying and heating mode. AnF/F (feedforward) control amount calculation section 58 of thecontroller 32 calculates an F/F control amount TGNChff of the compressortarget number of revolution on the basis of an outdoor air temperatureTam obtained from the outdoor air temperature sensor 33, a blowervoltage BLV of the indoor blower 27, an air mix damper opening SW of theair mix damper 28 which is obtained in accordance withSW=(TAO−Te)/(TH−Te), a target subcool degree TGSC which is a targetvalue of a subcool degree SC in the outlet of the radiator 4, a radiatortarget temperature TCO which is a target value of the temperature of theradiator 4, and a radiator target pressure PCO which is a target valueof the pressure of the radiator 4.

It is to be noted that TAO is a target outlet temperature which is atarget value of an air temperature from the outlet 29, TH is thetemperature of the radiator 4 which is obtained from the radiatortemperature sensor 46 (the radiator temperature), and Te is thetemperature of the heat absorber 9 which is obtained from the heatabsorber temperature sensor 48 (the heat absorber temperature). The airmix damper opening SW varies in a range of 0≦SW≦1, 0 indicates an airmix shut off state where the air is not passed through the radiator 4,and 1 indicates an air mix fully opened state where all the air in theair flow passage 3 is passed through the radiator 4.

The above radiator target pressure PCO is calculated on the basis of theabove target subcool degree TGSC and the radiator target temperature TCOby a target value calculation section 59. Furthermore, an F/B (feedback)control amount calculation section 60 calculates an F/B control amountTGNChfb of the compressor target number of revolution on the basis ofthis radiator target pressure PCO and the radiator pressure PCI which isthe refrigerant pressure of the radiator 4. Furthermore, the F/F controlamount TGNCnff calculated by the F/F control amount calculation section58 and the control amount TGNChfb calculated by the F/B control amountcalculation section 60 are added by an adder 61, limits of an upperlimit of controlling and a lower limit of controlling are attached by alimit setting section 62, and then the compressor target number ofrevolution TGNCh is determined. In the above heating mode and thedehumidifying and heating mode, the controller 32 controls therevolution number of the compressor 2 on the basis of this compressortarget number of revolution TGNCh.

On the other hand, FIG. 4 is the control block diagram of the controller32 which determines a target number of revolution (a compressor targetnumber of revolution) TGNCc of the compressor 2 for the above coolingmode and the dehumidifying and cooling mode (an after-mentioned normalmode). An F/F control amount calculation section 63 of the controller 32calculates an F/F control amount TGNCcff of the compressor target numberof revolution on the basis of the outdoor air temperature Tam, theblower voltage BLV, and a heat absorber target temperature TEO which isa target value of the temperature of the heat absorber 9.

In addition, an F/B control amount calculation section 64 calculates anF/B control amount TGNCcfb of the compressor target number of revolutionon the basis of the heat absorber target temperature TEO and the heatabsorber temperature Te. Furthermore, the F/F control amount TGNCcffcalculated by the F/F control amount calculation section 63 and the F/Bcontrol amount TGNCcfb calculated by the F/B control amount calculationsection 64 are added by an adder 66, limits of an upper limit ofcontrolling and a lower limit of controlling are attached by a limitsetting section 67, and then the compressor target number of revolutionTGNCc is determined. In the cooling mode and the normal mode of thedehumidifying and cooling mode, the controller 32 controls therevolution number of the compressor 2 on the basis of this compressortarget number of revolution TGNCc.

It is to be noted that in the above internal cycle mode, the controller32 controls the revolution number of the compressor 2 by use of asmaller control amount in the compressor target number of revolutionTGNCh calculated for the heating mode and the dehumidifying and heatingmode and the compressor target number of revolution TGNCc calculated forthe cooling mode and the dehumidifying and cooling mode as describedabove.

Next, FIG. 5 is the control block diagram of the controller 32 whichdetermines a target position (an outdoor expansion valve targetposition) TGECCVpc of the outdoor expansion valve 6 in the dehumidifyingand cooling mode. An F/F control amount calculation section 68 of thecontroller 32 calculates an F/F control amount TGECCVpcff of the outdoorexpansion valve target position on the basis of the outdoor airtemperature Tam, the blower voltage BLV, the radiator target temperatureTCO, and the radiator target pressure PCO.

In addition, an F/B control amount calculation section 69 calculates anF/B control amount TGECCVpcfb of the outdoor expansion valve targetposition on the basis of the radiator target pressure PCO and theradiator pressure PCI. Furthermore, the F/F control amount TGECCVpcffcalculated by the F/F control amount calculation section 68 and the F/Bcontrol amount TGECCVpcfb calculated by the F/B control amountcalculation section 69 are added by an adder 71, limits of an upperlimit of controlling and a lower limit of controlling are attached by alimit setting section 72, and then the outdoor expansion valve targetposition TGECCVpc is determined. In the dehumidifying and cooling mode,the controller 32 controls the valve position of the outdoor expansionvalve 6 on the basis of this outdoor expansion valve target positionTGECCVpc.

The air flowing through the air flow passage 3 is subjected to thecooling from the heat absorber 9 and a heating operation from theradiator 4 (regulated by the air mix damper 28) in the above respectiveoperation modes, to be blown out into the vehicle interior from theoutlet 29. The controller 32 calculates the target outlet temperatureTAO on the basis of the outdoor air temperature Tam detected by theoutdoor air temperature sensor 33, the interior temperature which isdetected by the indoor air temperature sensor 37, the above blowervoltage, the solar radiation amount detected by the solar radiationsensor 51, and the like, and the target interior temperature (the settemperature) in the vehicle which is set by the operating portion 53,and each operation mode is changed to control the temperature of the airblown out from the outlet 29 into this target outlet temperature TAO asdescribed later.

Next, the changing control of the above respective operation modes bythe controller 32 will be described with reference to FIG. 6 to FIG. 9.

(6) Changing Control of Operation Mode

FIG. 6 shows the operation mode selected by the controller 32 of thevehicle air conditioner 1 on startup. On the startup, the controller 32selects the operation mode on the basis of the outdoor air temperatureTam detected by the outdoor air temperature sensor 33 and the targetoutlet temperature TAO. That is, in FIG. 6, a broken line L1 is a lineof the target outlet temperature TAO=the outdoor air temperature Tam,and a solid line L2 is a line of the target outlet temperature TAO=HVACsuction temperature (the temperature of the air sucked from the suctionport 25 to the air flow passage 3). In addition, a broken line L3 is aline of hysteresis set on a predetermined value (three degrees) abovethe solid line.

First, in the embodiment, when the outdoor air temperature Tam is 0° C.or less on the startup, the controller 32 selects the heating mode. Inaddition, when the outdoor air temperature Tam is higher than 0° C. andthe target outlet temperature TAO is the HVAC suction temperature orless, the controller selects the cooling mode. Furthermore, when theoutdoor air temperature Tam is higher than 0° C. and is a predeterminedvalue (e.g., 20° C. or the like) or less and when the target outlettemperature TAO is higher than the HVAC suction temperature, thecontroller selects the dehumidifying and heating mode, and further, whenthe outdoor air temperature Tam is higher than the predetermined value,the controller selects the dehumidifying and cooling mode. It is to benoted that when the outdoor air humidity detected by the outdoor airhumidity sensor 34 is a predetermined value (e.g., 50% or the like) orless on conditions for the selection of the dehumidifying and heatingmode, the controller selects the heating mode.

Next, FIG. 7 shows one example of the operation mode changing control bythe controller 32 after the start. When the controller 32 executes theabove heating mode, the controller shifts to the dehumidifying andheating mode, in a case where the outdoor air temperature Tam rises to,for example, 2° C. which is two degrees higher than 0° C., or more andthe outdoor air humidity rises to, for example, 50% or more, on thebasis of the outdoor air temperature sensor 33 and the outdoor airhumidity sensor 34. In addition, when the controller executes theheating mode, the controller skips over the dehumidifying and heatingmode to the dehumidifying and cooling mode, in a case where the outdoorair temperature Tam is higher than 0° C. mentioned above and rises to,for example, 22° C. which is two degrees higher than 20° C., or more andthe outdoor air humidity similarly rises to 50% or more.

In addition, when the controller 32 executes the above dehumidifying andheating mode and when the outdoor air temperature Tam lowers to 0° C. orless and the outdoor air humidity lowers to be less than, for example,45% which is 5% lower than 50%, the controller shifts to the heatingmode.

In addition, when the controller 32 executes the dehumidifying andheating mode, the controller shifts to the above internal cycle mode, ina case where the valve position of the outdoor expansion valve 6 is theabovementioned lower limit of controlling (e.g., a state where therefrigerant cannot be squeezed any more) and there is continued for apredetermined time or more a state where the heat absorber temperatureTe—the heat absorber target temperature TEO is, for example, two degreesor more (i.e., a state where the heat absorption in the heat absorber 9runs short) or a state where the radiator temperature TH—the radiatortarget temperature TCO is, for example, five degrees or more (i.e., astate where the heat radiation in the radiator 4 becomes excessive).

In addition, when the controller 32 executes the internal cycle mode,the controller shifts to the normal mode (a heat absorber temperatureprior mode) of the dehumidifying and cooling mode, in a case where thereis continued for a predetermined time or more a state where the heatabsorber temperature Te—the heat absorber target temperature TEO islarger than, for example, three degrees larger than two degreesmentioned above (i.e., a state where the heat absorption in the heatabsorber 9 further runs short) or a state where the radiator temperatureTH—the radiator target temperature TCO is, for example, ten degrees ormore which is larger than five degrees mentioned above (i.e., a statewhere the heat radiation in the radiator 4 further becomes excessive) ora state where the target outlet temperature TAO—the HVAC suctiontemperature is, for example, three degrees or less.

It is to be noted that when the controller executes the abovedehumidifying and heating mode, the controller 32 may shift directly tothe dehumidifying and cooling mode without shifting to the internalcycle mode, in the state where the heat absorption in the heat absorber9 runs short further from conditions for the shift from the aboveinternal cycle mode to the dehumidifying and cooling mode, the casewhere the heat radiation in the radiator 4 further becomes excessive, orthe like. In consequence, it is possible to more rapidly cope withchanges of environmental conditions, and the like.

In addition, the controller 32 changes and executes the normal mode andthe radiator temperature prior mode in this dehumidifying and coolingmode, but these normal mode and radiator temperature prior mode will bedescribed later in detail. Furthermore, when the controller 32 executesthe radiator temperature prior mode in this dehumidifying and coolingmode and when the radiator target temperature TCO—the radiatortemperature TH is larger than, for example, three degrees (i.e., theheat radiation in the radiator 4 runs short) and this state is continuedfor the predetermined time or more, the controller shifts to theinternal cycle mode.

In addition, when the controller 32 executes the internal cycle mode,the controller shifts to the dehumidifying and heating mode, in a casewhere there is continued for a predetermined time or more a state wherethe radiator target temperature TCO—the radiator temperature TH islarger than, for example, three degrees (i.e., the heat radiation in theradiator 4 runs short) or the heat absorber target temperature TEO—theheat absorber temperature Te is larger than, for example, two degrees(i.e., the heat absorption in the heat absorber 9 is excessive) and theHVAC suction temperature (the outdoor air suction temperature) is, forexample, 20° C. or less while the outdoor air is introduced.

It is to be noted that when the controller executes this internal cyclemode, the controller 32 may shift directly to the heating mode withoutshifting to the dehumidifying and heating mode, in the state where theheat radiation in the radiator 4 runs short further from the conditionsfor the shift to the above dehumidifying and heating mode, the casewhere the heat absorption in the heat absorber 9 further becomeexcessive, or the like. In consequence, it is possible to more rapidlycope with the changes of the environmental conditions, and the like inthe same manner as mentioned above.

Furthermore, when the controller 32 executes the dehumidifying andcooling mode and when the valve position of the outdoor expansion valve6 is the abovementioned upper limit of controlling (i.e., a state wherethe refrigerant is passed as it is) and the air mix damper opening SW ofthe air mix damper 28 is smaller than a predetermined value, thecontroller shifts to the cooling mode.

Additionally, when the controller 32 executes this cooling mode and whenthe air mix damper opening SW is the predetermined value or more and theradiator target temperature TCO—TH is, for example, three degrees ormore (i.e., the heat radiation in the radiator 4 runs short), thecontroller shifts to the dehumidifying and cooling mode.

When the controller 32 changes the operation mode in this manner, it ispossible to accurately change the operation mode among the dehumidifyingand heating mode, the internal cycle mode and the dehumidifying andcooling mode in accordance with a situation where the heat radiation inthe radiator 4 or the heat absorption in the heat absorber 9 runs shortor becomes excessive on conditions such as the environment of thevehicle and the set temperature.

In addition, it is possible to accurately change the operation modeamong the heating mode, the dehumidifying and heating mode and thedehumidifying and cooling mode in accordance with an outdoor airenvironment, and it is also possible to shift from the heating modedirectly to the dehumidifying and cooling mode in a situation where thetemperature further rises in the outdoor air environment. Furthermore,it is possible to accurately change the operation mode between thecooling mode and the dehumidifying and cooling mode in accordance with acontrol situation of the outdoor expansion valve 6 or the situation ofthe heat radiation of the radiator 4.

(6-1) Other Operation Mode Changing Control

It is to be noted that as described above, it can be considered that theinternal cycle mode is the state where the outdoor expansion valve 6 isshut off by the control of the outdoor expansion valve 6 in thedehumidifying and heating mode. FIG. 8 shows one example of theoperation mode changing control by the controller 32 after the start inthe case of a control logic of the outdoor expansion valve 6 whichshifts from the dehumidifying and heating mode to the internal cyclemode as it is.

In this case, the internal cycle mode is included in the dehumidifyingand heating mode. In addition, conditions for the shift from thedehumidifying and heating mode to the dehumidifying and cooling mode aresimilar to the abovementioned conditions for the shift from the internalcycle mode to the dehumidifying and cooling mode.

(6-2) Indoor/Outdoor Air Control

Next, FIG. 9 shows one example of the control of the suction changingdamper 26 by the controller 32. As described above, the suction changingdamper 26 changes the outdoor air introducing mode to introduce theoutdoor air into the air flow passage 3 and the indoor air circulatingmode to introduce the air into the vehicle, but such indoor/outdoor aircontrol varies on the startup and in the stable condition after thestart.

That is, on the startup of the vehicle air conditioner 1 (an absolutevalue of a difference between a set interior temperature and theinterior temperature is a predetermined value or less), when thecontroller 32 executes the heating mode or the dehumidifying and heatingmode (including the internal cycle mode), the controller transfers thesuction changing damper 26 to the outdoor air introducing mode, in acase where the outdoor air temperature obtained from the outdoor airtemperature sensor 33 is not less than the indoor air temperatureobtained from the indoor air temperature sensor 37 (i.e., at least acase where the outdoor air temperature is higher than an interiortemperature is included), or an interior humidity obtained from theindoor air humidity sensor 38 is higher than the outdoor air humidityobtained from the outdoor air humidity sensor 34. Furthermore, thecontroller transfers the suction changing damper to the indoor aircirculating mode, in a case where the interior temperature is higherthan the outdoor air temperature or the outdoor air humidity is not lessthan the interior humidity (i.e., at least a case where the outdoor airhumidity is higher than the interior humidity is included).

In addition, when the controller 32 executes the cooling mode or thedehumidifying and cooling mode on the startup, the controller transfersthe suction changing damper 26 to the indoor air circulating mode, in acase where the outdoor air temperature is not less than the indoor airtemperature (i.e., at least a case where the outdoor air temperature ishigher than the interior temperature is included) or the outdoor airhumidity is not less than the indoor air humidity (i.e., at least a casewhere the outdoor air humidity is higher than the interior humidity isincluded). Furthermore, the controller transfers the suction changingdamper to the outdoor air introducing mode, in a case where the interiortemperature is higher than the outdoor air temperature or the interiorhumidity is higher than the outdoor air humidity.

On the other hand, in the stable condition after the start (the interiortemperature is substantially equal to the set temperature), thecontroller 32 transfers the suction changing damper 26 to the outdoorair introducing mode, in a case where the carbon dioxide concentrationin the vehicle interior which is obtained from the indoor air CO₂concentration sensor 39 is high and is a predetermined value or more, orthe indoor air circulating mode is continued for the predetermined timeor more (the indoor air introducing time is a predetermined value ormore), or the interior humidity is higher than the outdoor air humidity,or the target outlet temperature TAO which is the target value of thetemperature of the air blown out into the vehicle interior is the sameas or close to the outdoor air temperature (a difference α).Furthermore, the controller transfers the suction changing damper to theindoor air circulating mode, in a case other than the above cases, i.e.,in a case where the concentration of carbon dioxide in the vehicle islower than the predetermined value, or the outdoor air humidity is notless than the indoor air humidity, or the outdoor air temperature isnoticeably different from the target outlet temperature TAO (thedifference is larger than α).

When the suction changing damper 26 is controlled in this manner and theheating mode or the dehumidifying and heating mode is executed on thestartup, the outdoor air introducing mode and the indoor air circulatingmode are accurately changed in accordance with the outdoor airenvironment, so that it is possible to effectively utilize the heat inthe outdoor air for the heating in the vehicle. In addition, when thecooling mode or the dehumidifying and cooling mode is executed on thestartup, the outdoor air introducing mode and the indoor air circulatingmode are accurately changed in accordance with the outdoor airenvironment, so that it is possible to eliminate a bad influence of theheat in the outdoor air on the cooling in the vehicle, or effectivelyutilize cold in the outdoor air for the cooling in the vehicle.Furthermore, it is possible to accurately change the outdoor airintroducing mode and the indoor air circulating mode in accordance withthe carbon dioxide concentration in the vehicle interior or the targetoutlet temperature in the stable condition after the start.

It is to be noted that in the above embodiment, the suction changingdamper 26 changes the outdoor air introducing mode to introduce theoutdoor air into the air flow passage 3 and the indoor air circulatingmode to introduce the air in the vehicle interior (the indoor air), butthe present invention is not limited to this example, and between astate where all the outdoor air is introduced and a state where all theair in the vehicle interior is introduced, control may be executed tocontinuously regulate a mixture degree of the outdoor air and the indoorair (an amount of the indoor air to be mixed). Also in this case, adirection of the control on the conditions of the outdoor airtemperature, the indoor air temperature, the outdoor air humidity, theindoor air humidity and the carbon dioxide concentration in the vehicleinterior is similar to that of the above embodiment.

Furthermore, in accordance with the above changing control of theoperation mode, according to the vehicle air conditioner 1 of theembodiment, it is possible to select and change the optimum operationmode on conditions such as the environment of the vehicle and the settemperature so that a desirable air conditioning performance can beexerted, and the desirable air conditioning performance is exerted sothat comfortable air condition in the vehicle can be realized.

(7) Normal Mode and Radiator Temperature Prior Mode in Dehumidifying andCooling Mode

Next, the changing control of the normal mode (the heat absorbertemperature prior mode) and the radiator temperature prior mode in theabovementioned dehumidifying and cooling mode will be described withreference to FIG. 10 to FIG. 22. As described above, in the normal modeof the dehumidifying and cooling mode, the revolution number (the targetnumber of revolution TGNCc) of the compressor 2 is controlled by thetemperature of the heat absorber 9 (the heat absorber temperature Te).Therefore, even in a state (a squeezed state) where the heat absorbertemperature Te converges at the heat absorber target temperature TEO andthe valve position of the outdoor expansion valve 6 has theabovementioned lower limit of controlling, the high pressure of therefrigerant circuit R does not rise, and the radiator pressure PCI doesnot reach the radiator target pressure PCO. In this case, thetemperature of the radiator 4 (the radiator temperature TCO) causesshortage.

To solve the problem, in such a case, the controller 32 executes theradiator temperature prior mode in which the heat absorber targettemperature TEO is lowered to raise the revolution number of thecompressor 2, the capability of the compressor 2 is enlarged to raisethe high pressure, and the radiator pressure PCI is raised to theradiator target pressure PCO. FIG. 10 shows the mode changing controlbetween the normal mode and the radiator temperature prior mode in thedehumidifying and cooling mode. When the controller 32 executes thedehumidifying and cooling mode (the normal mode in which the heatabsorber temperature is prioritized), the controller shifts to theradiator temperature prior mode, in a case where there is continued fora predetermined time or more a state where the valve position of theoutdoor expansion valve 6 is the above lower limit of controlling orless and the radiator target temperature TCO—the radiator temperature THis, for example, one degree or more (i.e., the heat radiation in theradiator 4 runs short).

FIG. 11 shows one example of a control block diagram of the controller32 in this radiator temperature prior mode. That is, 74 of FIG. 11 is adata table of a heat absorber basic target temperature TEO0, and thistable is set correspondingly to the outdoor air temperature beforehand.It is to be noted that this heat absorber basic target temperature TEO0is a heat absorber temperature to obtain the humidity required for theenvironment of the outdoor air temperature. Usually, the heat absorbertarget temperature TEO is determined on the basis of the data table 74,but in this radiator temperature prior mode, the controller 32 makes acorrection on the basis of an integrated value of a difference betweenthe radiator target pressure PCO and the radiator pressure PCI.

That is, the radiator target pressure PCO and the radiator pressure PCIobtained from the radiator pressure sensor 47 are input into asubtracter 76, and a deviation e is amplified by an amplifier 77 andinput into a calculator 78. The calculator 78 performs an integratingcalculation of a heat absorber temperature offset for a predeterminedintegrating period and integrating time, and an integrated value TEOPCOof the heat absorber temperature offset added to a previous value by anadder 79 is calculated. Furthermore, a limit setting section 81 attacheslimits of the upper limit of controlling and the lower limit ofcontrolling, and then a heat absorber temperature offset TEOPC isdetermined.

The heat absorber temperature offset TEOPC is subtracted from the heatabsorber basic target temperature TEO0 in a subtracter 82, and the heatabsorber target temperature TEO is determined. Therefore, as comparedwith the normal mode, the heat absorber target temperature TEO islowered as much as the heat absorber temperature offset TEOPC, wherebythe compressor target number of revolution TGNCc of the compressor 2 israised, the revolution number of the compressor 2 rises, the capabilityof the compressor 2 enlarges to raise the high pressure, and theradiator pressure PCI rises, so that the required temperature TH of theradiator 4 can be obtained.

It is to be noted that the limit setting section 81 limits the heatabsorber temperature offset TEOPC in a range where the heat absorber 9is not frosted. FIG. 12 is a timing chart to explain this behavior. Itis seen that when the situation where the outdoor expansion valve 6 hasthe lower limit of controlling shifts to the radiator temperature priormode on the abovementioned conditions in a state where the heat absorbertemperature Te converges at the heat absorber target temperature TEO andthe revolution number of the compressor 2 is low in the normal mode, therevolution number of the compressor 2 rises, the heat absorbertemperature Te lowers, and the radiator pressure PCI (or the radiatortemperature TH) rises.

On the other hand, in this radiator temperature prior mode, when a statewhere the heat absorber temperature offset TEOPC mentioned above becomeszero and the radiator temperature TH—the radiator target temperature TCOis higher than, for example, one degree (i.e., the heat radiation of theradiator 4 is excessive) is continued for a predetermined time or more,the controller 32 returns from the radiator temperature prior mode tothe normal mode.

It is to be noted that this changing control of the normal mode and theradiator temperature prior mode is similarly applicable also to a casewhere the revolution number of the compressor 2 is controlled by usingthe compressor target number of revolution TGNCc calculated for thecooling mode and the dehumidifying and cooling mode in the internalcycle mode.

Consequently, in the dehumidifying and cooling mode or the internalcycle mode, when the temperature TH of the radiator 4 causes shortageeven in a case where the temperature Te of the heat absorber 9 convergesat the target value TEO and the valve position of the outdoor expansionvalve 6 has the lower limit of controlling, the capability of theradiator compressor 2 enlarges to raise the high pressure, and theamount of the refrigerant to be radiated in the radiator 4 is enlarged,so that the reheating by the radiator 4 in the dehumidifying and coolingmode is acquired, thereby making it possible to acquire the airconditioning performance, and an effective range of the dehumidifyingand cooling mode is enlarged, thereby making it possible to realize thecomfortable air condition in the vehicle. In this case, the controller32 corrects and lowers the heat absorber target temperature TEO in therange where the heat absorber 9 is not frosted, and hence it is possibleto prevent occurrence of the frosting due to an excessive temperaturedrop of the heat absorber 9, so that energy saving can be achieved.

(7-1) Coordinated Controlling with Electric Heater

Here, when the temperature TH of the radiator 4 does not rise to theradiator target temperature TCO even by the rise of the revolutionnumber of the compressor 2 due to the lowering of the heat absorbertarget temperature TEO, the electric heater 57 may be utilized. FIG. 13to FIG. 15 show control of the radiator temperature prior mode by thecoordinated controlling with the electric heater 57. Also in this case,the conditions for the shift from the normal mode to the radiatortemperature prior mode are similar to those of FIG. 10. FIG. 14 shows aflowchart of the controller 32 in this case. In step S1, it is judgedwhether or not the current mode is the dehumidifying and cooling modeand the radiator temperature prior mode, and when yes, the step advancesto step S2, to allow the controlling of the electric heater 57.

FIG. 15 shows a control block diagram of the electric heater 57 by thecontroller 32 when the controlling of the electric heater 57 is allowed.That is, the radiator target temperature TCO (may be the radiator targetpressure PCO) and the radiator temperature TH obtained from the radiatortemperature sensor 46 (which may be the radiator pressure PCI) are inputinto a subtracter 83, and the deviation e is amplified by an amplifier84 and input into an calculator 86. The calculator 86 performs anintegrating calculation of an electric heater power Phtr for apredetermined integrating period and integrating time, and an integratedvalue of the electric heater power added to the previous value by theadder 87 is calculated. Furthermore, a limit setting section 88 attacheslimits of an upper limit of controlling and a lower limit ofcontrolling, and then the electric heater power Phtr is determined.

The controller 32 energizes the electric heater 57 in accordance with acontrol amount of the electric heater power Phtr to generate heat, andhence the shortage of the temperature of the radiator 4 is complementedby the electric heater 57, and it is possible to realize furthercomfortable air condition in the vehicle. It is to be noted thatconditions for the return to the normal mode in this case include theelectric heater power Phtr=0 in place of the abovementioned heatabsorber temperature offset TEOPC=0 (FIG. 13).

(7-2) Coordinated Controlling with Indoor Blower (Blower Fan)

In addition, when an air volume of the indoor blower 27 is raised, anamount of the heat to be absorbed in the heat absorber 9 increases,whereby the high pressure also rises to raise the radiator temperatureTH. Therefore, in place of or in addition to this coordination with theelectric heater 57, the indoor blower 27 may be coordinated to acquirethe radiator temperature TH. FIG. 16 to FIG. 18 show the control of theradiator temperature prior mode by the coordination with the indoorblower 27. Also in this case, the conditions for the shift from thenormal mode to the radiator temperature prior mode are similar to thoseof FIG. 10. FIG. 17 shows a flowchart of the controller 32 in this case.In step S3, it is judged whether or not the current mode is thedehumidifying and cooling mode and the radiator temperature prior mode,and when yes, the step advances to step S4 to judge whether or not AUTOfor the controlling of the indoor blower 27 is selected (i.e., the modeis not a manual mode). In the case of AUTO, the step advances to step S5to allow the coordinated controlling of the indoor blower.

FIG. 18 shows a control block diagram of the indoor blower 27 by thecontroller 32 when the coordinated controlling of the indoor blower (theblower fan) 27 is allowed. That is, 92 of FIG. 18 is a data table of ablower voltage basic value BLV0, and this table is set correspondinglyto the target outlet temperature TAO beforehand. It is to be noted thatthis blower voltage basic value BLV0 is a blower voltage to obtain theair volume of the indoor blower 27 which is suitable for the targetoutlet temperature TAO. Usually, the blower voltage BLV is determined onthe basis of the data table 92, but in this radiator temperature priormode, the controller 32 makes a correction on the basis of an integratedvalue of a difference between the radiator target temperature TCO (maybe the radiator target pressure PCO) and the radiator temperature TH(may be the radiator pressure PCI).

That is, the radiator target temperature TCO and the radiatortemperature TH obtained from the radiator temperature sensor 46 areinput into a subtracter 97, and the deviation e is amplified by anamplifier 89 and input into a calculator 91. The calculator 91 performsan integrating calculation of a blower voltage offset for apredetermined integrating period and integrating time, and an integratedvalue of the blower voltage offset added to the previous value by anadder 93 is calculated. Furthermore, a limit setting section 94 attacheslimits of an upper limit of controlling and a lower limit ofcontrolling, and then a blower voltage offset BLVhtr is determined.

The blower voltage offset BLVhtr is added to the blower voltage basicvalue BLV0 in an adder 96, and the blower voltage BLV is determined.Therefore, as compared with the normal mode, the blower voltage BLV israised as much as the blower voltage offset BLVhtr, whereby the airvolume of the indoor blower 27 enlarges, the amount of the heat to beabsorbed in the heat absorber 9 enlarges, the high pressure rises toraise the radiator pressure PCI, and the temperature TH of the radiator4 rises. In consequence, it is possible to further rapidly eliminate theshortage of the temperature of the radiator 4. It is to be noted thatconditions for the return to the normal mode include the blower voltageoffset BLVhtr=0 in place of the heat absorber temperature offset TEOPC=0of FIG. 10 (FIG. 16).

(7-3) Coordinated Controlling with Indoor/Outdoor Air Control

In addition, indoor/outdoor air control of the outdoor air introductionand indoor air circulation may be coordinated to raise the radiatortemperature TH. That is, when the air having a higher temperature in theindoor temperature (the indoor air temperature) and the outdoor airtemperature is introduced into the air flow passage 3, the amount of theheat to be absorbed in the heat absorber 9 increases, whereby the highpressure also rises to raise the radiator temperature TH. Therefore, inplace of or in addition to the above coordination with the electricheater 57 or the indoor blower 27, the indoor/outdoor air control by thesuction changing damper 26 may be coordinated to acquire the radiatortemperature TH. FIG. 19 and FIG. 20 show the control of the radiatortemperature prior mode by this coordination with the indoor/outdoor aircontrol.

Also in this case, the conditions for the shift from the normal mode tothe radiator temperature prior mode are similar to those of FIG. 10.FIG. 20 shows a flowchart of the controller 32 in this case. In step S6,it is judged whether or not the current mode is the dehumidifying andcooling mode and the radiator temperature prior mode, and when yes, thestep advances to step S7 to judge whether or not AUTO for theindoor/outdoor air control by the suction changing damper 26 is selected(i.e., the mode is not a manual mode). In the case of AUTO, the stepadvances to step S8 to judge whether or not the current mode is theoutdoor air introducing mode. When the current mode is the outdoor airintroducing mode, the controller 32 advances to step S9 to judge whetheror not the interior temperature (the indoor air temperature) obtainedfrom the indoor air temperature sensor 37 is higher than the outdoor airtemperature obtained from the outdoor air temperature sensor 33 and theindoor air CO₂ concentration obtained from the indoor air CO₂concentration sensor 39 is lower than a predetermined value.Furthermore, when the interior temperature is higher than the outdoorair temperature and the indoor air CO₂ concentration is lower than thepredetermined value, the step advances to step S10 in which the suctionchanging damper 26 changes to the indoor air circulating mode.

When the indoor air circulating mode is present in the step S8 and whenin the step S9, the outdoor air temperature is the interior temperature(the indoor air temperature) or more (i.e., the case where the outdoorair temperature is higher than the interior temperature is included) orthe indoor air CO₂ concentration is the predetermined value or more, thestep advances to step S11. In the step S11, the controller 32 judgeswhether or not the outdoor air temperature is higher than the interiortemperature, and when the outdoor air temperature is higher, the stepadvances to step S12 in which the suction changing damper 26 changes tothe outdoor air introducing mode. In consequence, the air having thehigher temperature in the interior air and the outdoor air is passedthrough the heat absorber 9. Therefore, the amount of the heat to beabsorbed in the heat absorber 9 is enlarged and the high pressure israised, so that it is possible to further rapidly eliminate thetemperature shortage of the radiator 4.

(7-4) Coordinated Controlling with Other Indoor/Outdoor Air Control

Here, there will be described the coordinated controlling in a casewhere an amount of the indoor air to be mixed with the outdoor air canbe regulated in the above indoor/outdoor air control of the suctionchanging damper 26 with reference to FIG. 21 and FIG. 22. FIG. 21 showsa flowchart of the controller 32 in this case. In step S13, it is judgedwhether or not the current mode is the dehumidifying and cooling modeand the radiator temperature prior mode, and when yes, the step advancesto step S14 to judge whether or not AUTO for the indoor/outdoor aircontrol by the suction changing damper 26 is selected (i.e., the mode isnot a manual mode). In the case of AUTO, the step advances to step S15to allow the indoor/outdoor air coordinated controlling.

FIG. 22 shows a control block diagram of the suction changing damper 26by the controller 32 in a case where the indoor/outdoor air coordinatedcontrolling by the suction changing damper 26 is allowed. That is, 98 ofFIG. 22 is a data table of an indoor air mixing ratio basic valueRECratio0, and in this table, a map on the basis of the target outlettemperature TAO and the outdoor air temperature Tam is set beforehand.It is to be noted that the indoor air mixing ratio basic value RECratio0is an indoor air mixing ratio suitable for the target outlet temperatureTAO and the outdoor air temperature Tam at this time. Usually, theindoor air mixing ratio RECratio is determined on the basis of the datatable 98, but in this radiator temperature prior mode, the controller 32makes a correction on the basis of an integrated value of a differencebetween the radiator target temperature TCO (may be the radiator targetpressure PCO) and the radiator temperature TH (may be the radiatorpressure PCI).

That is, the radiator target temperature TCO and the radiatortemperature TH obtained from the radiator temperature sensor 46 areinput into a subtracter 101, and the deviation e is amplified by anamplifier 102 and input into a calculator 103. The calculator 103performs an integrating calculation of an indoor air mixing ratio offsetfor a predetermined integrating period and integrating time, and anintegrated value of the indoor air mixing ratio offset added to theprevious value in an adder 104 is calculated. Furthermore, a limitsetting section 106 attaches limits of an upper limit of controlling anda lower limit of controlling, and then an indoor air mixing ratio offsetRECratiohtr is determined.

The indoor air mixing ratio offset RECratiohtr is further corrected inan indoor/outdoor air temperature correcting section 107. Theindoor/outdoor air temperature correcting section 107 defines the indoorair mixing ratio offset RECratiohtr as a correction in a direction (+)to increase the indoor air mixing ratio when the interior temperature isthe outdoor air temperature or more, or conversely as a correction in adirection (−) to decrease the indoor air mixing ratio when the outdoorair temperature is higher than the interior temperature, the offset isthen added to an indoor air mixing ratio basic value RECratio0 in anadder 99, and the indoor air mixing ratio RECratio is determined.

Therefore, when the interior temperature is higher than the outdoor airtemperature, the indoor air mixing ratio RECratio is increased as muchas the indoor air mixing ratio offset RECratiohtr as compared with thenormal mode, whereby the amount of the heat to be absorbed in the heatabsorber 9 enlarges, the high pressure rises to raise the radiatorpressure PCI, and the temperature TH of the radiator 4 rises. Inconsequence, it is possible to further rapidly eliminate the temperatureshortage of the radiator 4.

It is to be noted that the constitution of the refrigerant circuit R andthe respective numeric values described in the above embodiment are notlimited, and are, needless to say, changeable without departing from thegist of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 vehicle air conditioner    -   2 compressor    -   3 air flow passage    -   4 radiator    -   6 outdoor expansion valve    -   6 outdoor heat exchanger    -   7 indoor expansion valve    -   8 heat absorber    -   11 evaporation capability control valve    -   17, 21, 22 and 23 solenoid valve    -   26 suction changing damper    -   27 indoor blower (a blower fan)    -   28 air mix damper    -   32 controller (control means)    -   57 electric heater    -   R refrigerant circuit

The invention claimed is:
 1. A vehicle air conditioner comprising: acompressor which compresses a refrigerant; an air flow passage throughwhich air to be supplied into a vehicle interior flows; a radiatordisposed in the air flow passage to let the refrigerant radiate heat; aheat absorber disposed in the air flow passage to let the refrigerantabsorb heat; an outdoor heat exchanger disposed outside the vehicleinterior to let the refrigerant radiate or absorb heat; and controlmeans being configured to change and execute at least one of: a heatingmode in which the refrigerant discharged from the compressor radiatesheat in the radiator, and the refrigerant by which heat has beenradiated is decompressed and then absorbs heat in the outdoor heatexchanger; a dehumidifying and heating mode in which the refrigerantdischarged from the compressor radiates heat in the radiator, and therefrigerant by which the heat has been radiated is decompressed and thenabsorbs heat only in the heat absorber or in the heat absorber and theoutdoor heat exchanger; a dehumidifying and cooling mode in which therefrigerant discharged from the compressor radiates heat in the radiatorand the outdoor heat exchanger, and the refrigerant by which the heathas been radiated is decompressed and then absorbs heat in the heatabsorber; and a cooling mode in which the refrigerant discharged fromthe compressor radiates heat in the outdoor heat exchanger, and therefrigerant by which the heat has been radiated is decompressed and thenabsorbs heat in the heat absorber, wherein the control means shifts tothe dehumidifying and cooling mode on the basis of a situation whereheat absorption in the heat absorber runs short or heat radiation in theradiator becomes excessive in the dehumidifying and heating mode, andalso shifts to the dehumidifying and heating mode on the basis of asituation where the heat radiation in the radiator runs short in thedehumidifying and cooling mode.
 2. The vehicle air conditioner accordingto claim 1, wherein the control means has, in the dehumidifying andheating mode, an internal cycle mode in which the refrigerant isinhibited from flowing into the outdoor heat exchanger and therefrigerant absorbs heat only in the heat absorber, wherein the controlmeans shifts to the internal cycle mode on the basis of a situationwhere the heat absorption in the heat absorber runs short or the heatradiation in the radiator becomes excessive in the dehumidifying andheating mode, and also shifts to the dehumidifying and cooling mode onthe basis of a situation where the heat absorption in the heat absorberfurther runs short or the heat radiation in the radiator further becomesexcessive in this internal cycle mode.
 3. The vehicle air conditioneraccording to claim 2, wherein the control means shifts to the internalcycle mode on the basis of the situation where the heat radiation in theradiator runs short in the dehumidifying and cooling mode, and alsoshifts to the dehumidifying and heating mode on the basis of thesituation where the heat radiation in the radiator runs short or theheat absorption in the heat absorber becomes excessive in this internalcycle mode.
 4. The vehicle air conditioner according to claim 3, whereinthe control means shifts from the heating mode to the dehumidifying andheating mode or the dehumidifying and cooling mode on the basis of asituation where an outdoor air temperature and an outdoor air humidityrise, and shifts from the dehumidifying and heating mode and thedehumidifying and cooling mode to the heating mode on the basis of asituation where the outdoor air temperature and the outdoor air humiditylower.
 5. The vehicle air conditioner according to claim 3, whichcomprises an expansion valve which decompresses the refrigerant flowinginto the outdoor heat exchanger, wherein the control means shifts fromthe dehumidifying and cooling mode to the cooling mode on the basis of asituation where a valve position of the expansion valve reaches an upperlimit of controlling, and shifts from the cooling mode to thedehumidifying and cooling mode on the basis of the situation where theheat radiation in the radiator runs short.
 6. The vehicle airconditioner according to claim 3, which comprises a suction changingdamper which changes an outdoor air introducing mode to introduce theoutdoor air into the air flow passage and an indoor air circulating modeto introduce the air in the vehicle interior into the air flow passage,wherein when the control means executes the heating mode or thedehumidifying and heating mode on startup, the control means transfersthe suction changing damper to the outdoor air introducing mode in acase where at least the outdoor air temperature is higher than aninterior temperature or at least an interior humidity is higher than theoutdoor air humidity, and to the indoor air circulating mode in a casewhere at least the interior temperature is higher than the outdoor airtemperature or at least the outdoor air humidity is higher than theinterior humidity.
 7. The vehicle air conditioner according to claim 6,wherein in a stable condition after the start, the control meanstransfers the suction changing damper to the outdoor air introducingmode in a case where a carbon dioxide concentration in the vehicleinterior is high, or the indoor air circulating mode is continued for apredetermined time or more, or the interior humidity is higher than theoutdoor air humidity, or a target value of a temperature of the airblown out into the vehicle interior is the same as or close to theoutdoor air temperature, and the control means transfers the suctionchanging damper to the indoor air circulating mode on conditions otherthan the above conditions.
 8. The vehicle air conditioner according toclaim 3, which comprises a suction changing damper which changes anoutdoor air introducing mode to introduce the outdoor air into the airflow passage and an indoor air circulating mode to introduce the air inthe vehicle interior into the air flow passage, wherein when the controlmeans executes the cooling mode or the dehumidifying and cooling mode onthe startup, the control means transfers the suction changing damper tothe indoor air circulating mode in a case where at least the outdoor airtemperature is higher than the interior temperature or at least theoutdoor air humidity is higher than the interior humidity, and to theoutdoor air introducing mode in a case where at least the interiortemperature is higher than the outdoor air temperature or at least theinterior humidity is higher than the outdoor air humidity.
 9. Thevehicle air conditioner according to claim 8, wherein in a stablecondition after the start, the control means transfers the suctionchanging damper to the outdoor air introducing mode in a case where acarbon dioxide concentration in the vehicle interior is high, or theindoor air circulating mode is continued for a predetermined time ormore, or the interior humidity is higher than the outdoor air humidity,or a target value of a temperature of the air blown out into the vehicleinterior is the same as or close to the outdoor air temperature, and thecontrol means transfers the suction changing damper to the indoor aircirculating mode on conditions other than the above conditions.
 10. Thevehicle air conditioner according to claim 2, wherein the control meansshifts from the heating mode to the dehumidifying and heating mode orthe dehumidifying and cooling mode on the basis of a situation where anoutdoor air temperature and an outdoor air humidity rise, and shiftsfrom the dehumidifying and heating mode and the dehumidifying andcooling mode to the heating mode on the basis of a situation where theoutdoor air temperature and the outdoor air humidity lower.
 11. Thevehicle air conditioner according to claim 2, which comprises anexpansion valve which decompresses the refrigerant flowing into theoutdoor heat exchanger, wherein the control means shifts from thedehumidifying and cooling mode to the cooling mode on the basis of asituation where a valve position of the expansion valve reaches an upperlimit of controlling, and shifts from the cooling mode to thedehumidifying and cooling mode on the basis of the situation where theheat radiation in the radiator runs short.
 12. The vehicle airconditioner according to claim 2, which comprises a suction changingdamper which changes an outdoor air introducing mode to introduce theoutdoor air into the air flow passage and an indoor air circulating modeto introduce the air in the vehicle interior into the air flow passage,wherein when the control means executes the heating mode or thedehumidifying and heating mode on startup, the control means transfersthe suction changing damper to the outdoor air introducing mode in acase where at least the outdoor air temperature is higher than aninterior temperature or at least an interior humidity is higher than theoutdoor air humidity, and to the indoor air circulating mode in a casewhere at least the interior temperature is higher than the outdoor airtemperature or at least the outdoor air humidity is higher than theinterior humidity.
 13. The vehicle air conditioner according to claim 2,which comprises a suction changing damper which changes an outdoor airintroducing mode to introduce the outdoor air into the air flow passageand an indoor air circulating mode to introduce the air in the vehicleinterior into the air flow passage, wherein when the control meansexecutes the cooling mode or the dehumidifying and cooling mode on thestartup, the control means transfers the suction changing damper to theindoor air circulating mode in a case where at least the outdoor airtemperature is higher than the interior temperature or at least theoutdoor air humidity is higher than the interior humidity, and to theoutdoor air introducing mode in a case where at least the interiortemperature is higher than the outdoor air temperature or at least theinterior humidity is higher than the outdoor air humidity.
 14. Thevehicle air conditioner according to claim 1, wherein the control meansshifts from the heating mode to the dehumidifying and heating mode orthe dehumidifying and cooling mode on the basis of a situation where anoutdoor air temperature and an outdoor air humidity rise, and shiftsfrom the dehumidifying and heating mode and the dehumidifying andcooling mode to the heating mode on the basis of a situation where theoutdoor air temperature and the outdoor air humidity lower.
 15. Thevehicle air conditioner according to claim 14, wherein the control meansshifts from the heating mode to the dehumidifying and cooling mode onthe basis of a situation where the outdoor air temperature rises to atemperature higher than a temperature of a condition for the shift fromthe heating mode to the dehumidifying and heating mode.
 16. The vehicleair conditioner according to claim 1, which comprises an expansion valvewhich decompresses the refrigerant flowing into the outdoor heatexchanger, wherein the control means shifts from the dehumidifying andcooling mode to the cooling mode on the basis of a situation where avalve position of the expansion valve reaches an upper limit ofcontrolling, and shifts from the cooling mode to the dehumidifying andcooling mode on the basis of the situation where the heat radiation inthe radiator runs short.
 17. The vehicle air conditioner according toclaim 1, which comprises a suction changing damper which changes anoutdoor air introducing mode to introduce the outdoor air into the airflow passage and an indoor air circulating mode to introduce the air inthe vehicle interior into the air flow passage, wherein when the controlmeans executes the heating mode or the dehumidifying and heating mode onstartup, the control means transfers the suction changing damper to theoutdoor air introducing mode in a case where at least the outdoor airtemperature is higher than an interior temperature or at least aninterior humidity is higher than the outdoor air humidity, and to theindoor air circulating mode in a case where at least the interiortemperature is higher than the outdoor air temperature or at least theoutdoor air humidity is higher than the interior humidity.
 18. Thevehicle air conditioner according to claim 17, wherein in a stablecondition after the start, the control means transfers the suctionchanging damper to the outdoor air introducing mode in a case where acarbon dioxide concentration in the vehicle interior is high, or theindoor air circulating mode is continued for a predetermined time ormore, or the interior humidity is higher than the outdoor air humidity,or a target value of a temperature of the air blown out into the vehicleinterior is the same as or close to the outdoor air temperature, and thecontrol means transfers the suction changing damper to the indoor aircirculating mode on conditions other than the above conditions.
 19. Thevehicle air conditioner according to claim 1, which comprises a suctionchanging damper which changes an outdoor air introducing mode tointroduce the outdoor air into the air flow passage and an indoor aircirculating mode to introduce the air in the vehicle interior into theair flow passage, wherein when the control means executes the coolingmode or the dehumidifying and cooling mode on the startup, the controlmeans transfers the suction changing damper to the indoor aircirculating mode in a case where at least the outdoor air temperature ishigher than the interior temperature or at least the outdoor airhumidity is higher than the interior humidity, and to the outdoor airintroducing mode in a case where at least the interior temperature ishigher than the outdoor air temperature or at least the interiorhumidity is higher than the outdoor air humidity.
 20. The vehicle airconditioner according to claim 19, wherein in a stable condition afterthe start, the control means transfers the suction changing damper tothe outdoor air introducing mode in a case where a carbon dioxideconcentration in the vehicle interior is high, or the indoor aircirculating mode is continued for a predetermined time or more, or theinterior humidity is higher than the outdoor air humidity, or a targetvalue of a temperature of the air blown out into the vehicle interior isthe same as or close to the outdoor air temperature, and the controlmeans transfers the suction changing damper to the indoor aircirculating mode on conditions other than the above conditions.